There are many reasons for extracting patients, some are due to apical inflammation, some are due to loose teeth, but teeth are located in the oral cavity have certain anatomical structures, some teeth are closer to important anatomical locations, such as mandibular teeth are closer to the mandibular nerve canal, some maxillary posterior teeth are closer to the maxillary sinus, when the patient extracts a tooth these ranges may be involved, so by taking a film you can avoid hurting these important during the intraoperative operation anatomical structures during intraoperative manipulation. In addition, many roots of the tooth are variable, with curved roots or a variable number of roots, and taking radiographs helps to make a good preoperative assessment, reduce the risk of intraoperative manipulation and avoid postoperative complications. Therefore, these important locations need to be identified by pre-extraction radiographs to avoid risks when extracting teeth.